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1// SPDX-License-Identifier: GPL-2.0
2#include <subcmd/parse-options.h>
3#include "evsel.h"
4#include "cgroup.h"
5#include "evlist.h"
6#include <linux/stringify.h>
7#include <linux/zalloc.h>
8#include <sys/types.h>
9#include <sys/stat.h>
10#include <fcntl.h>
11#include <stdlib.h>
12#include <string.h>
13
14int nr_cgroups;
15
16static int
17cgroupfs_find_mountpoint(char *buf, size_t maxlen)
18{
19 FILE *fp;
20 char mountpoint[PATH_MAX + 1], tokens[PATH_MAX + 1], type[PATH_MAX + 1];
21 char path_v1[PATH_MAX + 1], path_v2[PATH_MAX + 2], *path;
22 char *token, *saved_ptr = NULL;
23
24 fp = fopen("/proc/mounts", "r");
25 if (!fp)
26 return -1;
27
28 /*
29 * in order to handle split hierarchy, we need to scan /proc/mounts
30 * and inspect every cgroupfs mount point to find one that has
31 * perf_event subsystem
32 */
33 path_v1[0] = '\0';
34 path_v2[0] = '\0';
35
36 while (fscanf(fp, "%*s %"__stringify(PATH_MAX)"s %"__stringify(PATH_MAX)"s %"
37 __stringify(PATH_MAX)"s %*d %*d\n",
38 mountpoint, type, tokens) == 3) {
39
40 if (!path_v1[0] && !strcmp(type, "cgroup")) {
41
42 token = strtok_r(tokens, ",", &saved_ptr);
43
44 while (token != NULL) {
45 if (!strcmp(token, "perf_event")) {
46 strcpy(path_v1, mountpoint);
47 break;
48 }
49 token = strtok_r(NULL, ",", &saved_ptr);
50 }
51 }
52
53 if (!path_v2[0] && !strcmp(type, "cgroup2"))
54 strcpy(path_v2, mountpoint);
55
56 if (path_v1[0] && path_v2[0])
57 break;
58 }
59 fclose(fp);
60
61 if (path_v1[0])
62 path = path_v1;
63 else if (path_v2[0])
64 path = path_v2;
65 else
66 return -1;
67
68 if (strlen(path) < maxlen) {
69 strcpy(buf, path);
70 return 0;
71 }
72 return -1;
73}
74
75static int open_cgroup(const char *name)
76{
77 char path[PATH_MAX + 1];
78 char mnt[PATH_MAX + 1];
79 int fd;
80
81
82 if (cgroupfs_find_mountpoint(mnt, PATH_MAX + 1))
83 return -1;
84
85 scnprintf(path, PATH_MAX, "%s/%s", mnt, name);
86
87 fd = open(path, O_RDONLY);
88 if (fd == -1)
89 fprintf(stderr, "no access to cgroup %s\n", path);
90
91 return fd;
92}
93
94static struct cgroup *evlist__find_cgroup(struct evlist *evlist, const char *str)
95{
96 struct evsel *counter;
97 /*
98 * check if cgrp is already defined, if so we reuse it
99 */
100 evlist__for_each_entry(evlist, counter) {
101 if (!counter->cgrp)
102 continue;
103 if (!strcmp(counter->cgrp->name, str))
104 return cgroup__get(counter->cgrp);
105 }
106
107 return NULL;
108}
109
110static struct cgroup *cgroup__new(const char *name)
111{
112 struct cgroup *cgroup = zalloc(sizeof(*cgroup));
113
114 if (cgroup != NULL) {
115 refcount_set(&cgroup->refcnt, 1);
116
117 cgroup->name = strdup(name);
118 if (!cgroup->name)
119 goto out_err;
120 cgroup->fd = open_cgroup(name);
121 if (cgroup->fd == -1)
122 goto out_free_name;
123 }
124
125 return cgroup;
126
127out_free_name:
128 zfree(&cgroup->name);
129out_err:
130 free(cgroup);
131 return NULL;
132}
133
134struct cgroup *evlist__findnew_cgroup(struct evlist *evlist, const char *name)
135{
136 struct cgroup *cgroup = evlist__find_cgroup(evlist, name);
137
138 return cgroup ?: cgroup__new(name);
139}
140
141static int add_cgroup(struct evlist *evlist, const char *str)
142{
143 struct evsel *counter;
144 struct cgroup *cgrp = evlist__findnew_cgroup(evlist, str);
145 int n;
146
147 if (!cgrp)
148 return -1;
149 /*
150 * find corresponding event
151 * if add cgroup N, then need to find event N
152 */
153 n = 0;
154 evlist__for_each_entry(evlist, counter) {
155 if (n == nr_cgroups)
156 goto found;
157 n++;
158 }
159
160 cgroup__put(cgrp);
161 return -1;
162found:
163 counter->cgrp = cgrp;
164 return 0;
165}
166
167static void cgroup__delete(struct cgroup *cgroup)
168{
169 close(cgroup->fd);
170 zfree(&cgroup->name);
171 free(cgroup);
172}
173
174void cgroup__put(struct cgroup *cgrp)
175{
176 if (cgrp && refcount_dec_and_test(&cgrp->refcnt)) {
177 cgroup__delete(cgrp);
178 }
179}
180
181struct cgroup *cgroup__get(struct cgroup *cgroup)
182{
183 if (cgroup)
184 refcount_inc(&cgroup->refcnt);
185 return cgroup;
186}
187
188static void evsel__set_default_cgroup(struct evsel *evsel, struct cgroup *cgroup)
189{
190 if (evsel->cgrp == NULL)
191 evsel->cgrp = cgroup__get(cgroup);
192}
193
194void evlist__set_default_cgroup(struct evlist *evlist, struct cgroup *cgroup)
195{
196 struct evsel *evsel;
197
198 evlist__for_each_entry(evlist, evsel)
199 evsel__set_default_cgroup(evsel, cgroup);
200}
201
202int parse_cgroups(const struct option *opt, const char *str,
203 int unset __maybe_unused)
204{
205 struct evlist *evlist = *(struct evlist **)opt->value;
206 struct evsel *counter;
207 struct cgroup *cgrp = NULL;
208 const char *p, *e, *eos = str + strlen(str);
209 char *s;
210 int ret, i;
211
212 if (list_empty(&evlist->core.entries)) {
213 fprintf(stderr, "must define events before cgroups\n");
214 return -1;
215 }
216
217 for (;;) {
218 p = strchr(str, ',');
219 e = p ? p : eos;
220
221 /* allow empty cgroups, i.e., skip */
222 if (e - str) {
223 /* termination added */
224 s = strndup(str, e - str);
225 if (!s)
226 return -1;
227 ret = add_cgroup(evlist, s);
228 free(s);
229 if (ret)
230 return -1;
231 }
232 /* nr_cgroups is increased een for empty cgroups */
233 nr_cgroups++;
234 if (!p)
235 break;
236 str = p+1;
237 }
238 /* for the case one cgroup combine to multiple events */
239 i = 0;
240 if (nr_cgroups == 1) {
241 evlist__for_each_entry(evlist, counter) {
242 if (i == 0)
243 cgrp = counter->cgrp;
244 else {
245 counter->cgrp = cgrp;
246 refcount_inc(&cgrp->refcnt);
247 }
248 i++;
249 }
250 }
251 return 0;
252}
1#include "util.h"
2#include "../perf.h"
3#include "parse-options.h"
4#include "evsel.h"
5#include "cgroup.h"
6#include "debugfs.h" /* MAX_PATH, STR() */
7#include "evlist.h"
8
9int nr_cgroups;
10
11static int
12cgroupfs_find_mountpoint(char *buf, size_t maxlen)
13{
14 FILE *fp;
15 char mountpoint[MAX_PATH+1], tokens[MAX_PATH+1], type[MAX_PATH+1];
16 char *token, *saved_ptr = NULL;
17 int found = 0;
18
19 fp = fopen("/proc/mounts", "r");
20 if (!fp)
21 return -1;
22
23 /*
24 * in order to handle split hierarchy, we need to scan /proc/mounts
25 * and inspect every cgroupfs mount point to find one that has
26 * perf_event subsystem
27 */
28 while (fscanf(fp, "%*s %"STR(MAX_PATH)"s %"STR(MAX_PATH)"s %"
29 STR(MAX_PATH)"s %*d %*d\n",
30 mountpoint, type, tokens) == 3) {
31
32 if (!strcmp(type, "cgroup")) {
33
34 token = strtok_r(tokens, ",", &saved_ptr);
35
36 while (token != NULL) {
37 if (!strcmp(token, "perf_event")) {
38 found = 1;
39 break;
40 }
41 token = strtok_r(NULL, ",", &saved_ptr);
42 }
43 }
44 if (found)
45 break;
46 }
47 fclose(fp);
48 if (!found)
49 return -1;
50
51 if (strlen(mountpoint) < maxlen) {
52 strcpy(buf, mountpoint);
53 return 0;
54 }
55 return -1;
56}
57
58static int open_cgroup(char *name)
59{
60 char path[MAX_PATH+1];
61 char mnt[MAX_PATH+1];
62 int fd;
63
64
65 if (cgroupfs_find_mountpoint(mnt, MAX_PATH+1))
66 return -1;
67
68 snprintf(path, MAX_PATH, "%s/%s", mnt, name);
69
70 fd = open(path, O_RDONLY);
71 if (fd == -1)
72 fprintf(stderr, "no access to cgroup %s\n", path);
73
74 return fd;
75}
76
77static int add_cgroup(struct perf_evlist *evlist, char *str)
78{
79 struct perf_evsel *counter;
80 struct cgroup_sel *cgrp = NULL;
81 int n;
82 /*
83 * check if cgrp is already defined, if so we reuse it
84 */
85 list_for_each_entry(counter, &evlist->entries, node) {
86 cgrp = counter->cgrp;
87 if (!cgrp)
88 continue;
89 if (!strcmp(cgrp->name, str))
90 break;
91
92 cgrp = NULL;
93 }
94
95 if (!cgrp) {
96 cgrp = zalloc(sizeof(*cgrp));
97 if (!cgrp)
98 return -1;
99
100 cgrp->name = str;
101
102 cgrp->fd = open_cgroup(str);
103 if (cgrp->fd == -1) {
104 free(cgrp);
105 return -1;
106 }
107 }
108
109 /*
110 * find corresponding event
111 * if add cgroup N, then need to find event N
112 */
113 n = 0;
114 list_for_each_entry(counter, &evlist->entries, node) {
115 if (n == nr_cgroups)
116 goto found;
117 n++;
118 }
119 if (cgrp->refcnt == 0)
120 free(cgrp);
121
122 return -1;
123found:
124 cgrp->refcnt++;
125 counter->cgrp = cgrp;
126 return 0;
127}
128
129void close_cgroup(struct cgroup_sel *cgrp)
130{
131 if (!cgrp)
132 return;
133
134 /* XXX: not reentrant */
135 if (--cgrp->refcnt == 0) {
136 close(cgrp->fd);
137 free(cgrp->name);
138 free(cgrp);
139 }
140}
141
142int parse_cgroups(const struct option *opt __used, const char *str,
143 int unset __used)
144{
145 struct perf_evlist *evlist = *(struct perf_evlist **)opt->value;
146 const char *p, *e, *eos = str + strlen(str);
147 char *s;
148 int ret;
149
150 if (list_empty(&evlist->entries)) {
151 fprintf(stderr, "must define events before cgroups\n");
152 return -1;
153 }
154
155 for (;;) {
156 p = strchr(str, ',');
157 e = p ? p : eos;
158
159 /* allow empty cgroups, i.e., skip */
160 if (e - str) {
161 /* termination added */
162 s = strndup(str, e - str);
163 if (!s)
164 return -1;
165 ret = add_cgroup(evlist, s);
166 if (ret) {
167 free(s);
168 return -1;
169 }
170 }
171 /* nr_cgroups is increased een for empty cgroups */
172 nr_cgroups++;
173 if (!p)
174 break;
175 str = p+1;
176 }
177 return 0;
178}